In the British Museum, Greek and Roman Antiquities Department, this nicolo gem is engraved with an elephant emerging from a snail-shell .
According to Henig  this is a sea shell, but nevertheless I’m mentioning this object in this series. Is there any logic why an elephant would come out of a sea shell, when the Romans also used land shells as ornamentation?
 BML, inv. [GRA] 1804.0704.1407. http://to.ly/zGpQ.
 Henig, M. (1984). The Elephant and the Sea-shell. Oxford Journal of Archaeology 3: 243–247.